U.S. patent application number 15/051459 was filed with the patent office on 2016-08-25 for catalyst for olefin polymerization and polymerization thereof.
The applicant listed for this patent is INDIAN OIL CORPORATION LIMITED. Invention is credited to Bhasker BANTU, Biswajit BASU, Gurpreet Singh KAPUR, Sukhdeep KAUR, Naresh KUMAR, Ravinder Kumar MALHOTRA, Mohasin MOMIN, Rashmi RANI, Shashikant, Gurmeet SINGH.
Application Number | 20160244537 15/051459 |
Document ID | / |
Family ID | 56690273 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160244537 |
Kind Code |
A1 |
SINGH; Gurmeet ; et
al. |
August 25, 2016 |
CATALYST FOR OLEFIN POLYMERIZATION AND POLYMERIZATION THEREOF
Abstract
The present invention describes a process for preparing catalyst
for the polymerization of ethylene consisting essentially of the
steps of (i) contacting a magnesium based precursor with a solvent;
and (ii) then contacting the magnesium based precursor in the
solvent with a transition metal compound to obtain the catalyst,
wherein step (ii) is single contact step. The present invention
also relates to a process for preparation of a catalyst system and
a process of polymerizing and/or copolymerizing of ethylene to
obtain a polyethylene using the catalyst.
Inventors: |
SINGH; Gurmeet; (Faridabad,
IN) ; KUMAR; Naresh; (Faridabad, IN) ; BANTU;
Bhasker; (Faridabad, IN) ; KAUR; Sukhdeep;
(Faridabad, IN) ; RANI; Rashmi; (Faridabad,
IN) ; MOMIN; Mohasin; (Faridabad, IN) ; KAPUR;
Gurpreet Singh; (Faridabad, IN) ; Shashikant;;
(Faridabad, IN) ; BASU; Biswajit; (Faridabad,
IN) ; MALHOTRA; Ravinder Kumar; (Faridabad,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INDIAN OIL CORPORATION LIMITED |
Mumbai |
|
IN |
|
|
Family ID: |
56690273 |
Appl. No.: |
15/051459 |
Filed: |
February 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 210/16 20130101;
C08F 210/08 20130101; C08F 2500/18 20130101; C08F 2500/18 20130101;
C08F 4/6541 20130101; C08F 2500/18 20130101; C08F 2500/12 20130101;
C08F 10/02 20130101; C08F 2500/10 20130101; C08F 2500/12 20130101;
C08F 2500/12 20130101; C08F 110/02 20130101; C08F 210/16 20130101;
C08F 10/02 20130101; C08F 210/08 20130101 |
International
Class: |
C08F 10/02 20060101
C08F010/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2015 |
IN |
591/MUM/2015 |
Claims
1. A process for preparing catalyst for the polymerization of
ethylene consisting essentially of the steps of: contacting a
magnesium based precursor with a solvent; and (ii) then contacting
the magnesium based precursor in the solvent with a transition
metal compound to obtain the catalyst, wherein step (ii) is single
contact step.
2. The process as claimed in claim 1, wherein the solvent is
aromatic or aliphatic and polar or non polar in nature, and is
selected from group comprising of benzene, decane, kerosene, ethyl
benzene, chlorobenzene, dichlorobenzene, toluene, o-chlorotoluene,
xylene, dichloromethane, chloroform, cyclohexane and combination
thereof.
3. The process as claimed in claim 1, wherein the contact time with
the solvent in step (i) is immediate to 5 h.
4. The process as claimed in claim 1, wherein the contact
temperature with the solvent in step (i) is from 10.degree. C. to
200.degree. C.
5. The process as claimed in claim 1, wherein the magnesium based
precursor contains magnesium which is liquid or solid in
nature.
6. The process as claimed in claim 1, wherein the magnesium based
precursor is liquid in nature and prepared by contacting magnesium
source with organohalide and alcohol in presence of the solvent in
a single step.
7. The process as claimed in claim 1, wherein the magnesium based
precursor is solid in nature and is prepared by first contacting
the magnesium source with organohalide in presence of solvating
agent as the first step and then followed by addition of
alcohol.
8. The process as claimed in claim 1, wherein the magnesium based
precursor is contacted with solvent prior to transition metal
contact.
9. The process as claimed in claim 1, wherein the transition metal
compound is represented by M(OR).sub.pX.sub.4-p, where M is
selected from a group comprising of Ti, V, Zr, and Hf,; X is a
halogen atom; R is a hydrocarbon group and p is an integer having
value equal or less than 4, the transition metal compound is
selected from a group comprising of transition metal tetrahalide,
alkoxy transition metal trihalide/aryloxy transition metal
trihalide, dialkoxy transition metal dihalide, trialkoxy transition
metal monohalide, tetraalkoxy transition metal, and mixtures
thereof; wherein: (a) the transition metal tetrahalide is selected
from a group comprising of titanium tetrachloride, titanium
tetrabromide and titanium tetraiodide and the likes for V, Zr and
Hf; (b) alkoxy transition metal trihalide/aryloxy transition metal
trihalide is selected from a group comprising of methoxytitanium
trichloride, ethoxytitanium trichloride, butoxytitanium trichloride
and phenoxytitanium trichloride and the likes for V, Zr and Hf; (c)
dialkoxy transition metal dihalide is diethoxy titanium dichloride
and the likes for V, Zr and Hf; (d) trialkoxy transition metal
monohalide is triethoxy titanium chloride and the likes for V, Zr
and Hf; and (e) tetraalkoxy transition metal is selected from a
group comprising of tetrabutoxy titanium and tetraethoxy titanium
and the likes for V, Zr and Hf.
10. The process as claimed in claim 1, wherein the contact
temperature with the transition metal compound in step (ii) is
between -50.degree. C. and 150.degree. C.
11. The process as claimed in claim 1, wherein the titanium
compound is added in amounts ranging from 1 to 20 moles with
respect to one mole of magnesium.
12. The process as claimed in claim 1, wherein the transition metal
compound is used either neat or in solvent and wherein the solvent
is selected from a group comprising of chlorinated aromatic
hydrocarbon, non chlorinated aromatic hydrocarbon, chlorinated
aliphatic hydrocarbon, non chlorinated aliphatic hydrocarbon and
combination thereof.
13. The process as claimed in claim 1, wherein the solvent is
comprising from 40 to 60 volume percent and selected from a group
comprising of benzene, decane, kerosene, ethyl benzene,
chlorobenzene, dichlorobenzene, toluene, o-chlorotoluene, xylene,
dichloromethane, chloroform, cyclohexane and combination
thereof.
14. The process as claimed in claim 1, wherein the contact
temperature with the transition metal compound in step (ii) is
between -50.degree. C. and 150.degree. C. and heating is instigated
at a rate of 0.1 to 10.0.degree. C./minute.
15. A catalyst comprising 1.0 wt % to 14 wt % of titanium and 10 wt
% to 20 wt % of magnesium.
16. A process for preparation of a catalyst system, said process
comprising contacting the catalyst as obtained by claim 1 with at
least one cocatalyst, and optionally with an external electron
donor to obtain the catalyst system.
17. A process of polymerizing and/or copolymerizing of ethylene to
obtain a polyethylene said process comprising the step of
contacting an ethylene under a polymerizing condition with the
catalyst system as obtained by claim 16.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a process for preparing
catalyst using magnesium based precursor along with transition
metal for the polymerization of ethylene.
BACKGROUND OF THE INVENTION
[0002] Ziegler-Natta catalyst systems are well known for their
capability to polymerize olefins. They in general consist of a
support which mostly is magnesium based onto which titanium
component has been added along with organic compound known as
internal donor. This catalyst when combined with co-catalyst and/or
external donor comprise of the complete ZN catalyst system. Various
internal donors are incorporated during catalyst synthesis to
enhance specific properties of the polyethylene catalyst. Internal
donors like tetrahydrofuran, ethyl benzoate, tetraethoxysilane,
dimethylformamide etc are well known commercially used in
polyethylene catalyst.
[0003] U.S. Pat. No. 4,859,749 describes two-stage polymerization
process using a modified supported catalyst for ethylene polymers.
The supported catalyst used is formed by reaction of a magnesium
alcoholate with a titanium-IV compound in suspension and subsequent
reaction with a halogen-containing organoaluminum compound and
activation of the solid thus obtained by an aluminum trialkyl or
aluminum isoprenyl. This catalyst has the disadvantage of
generating higher amount of undesirable side products which act as
either poison and hence lowers the catalyst activity or generate
low molecular weight polyethylene which leads to fouling.
[0004] U.S. Pat. No. 5,260,245 describes a catalyst for producing
higher flow index linear low density polyethylene with relatively
narrower molecular weight distributions using catalyst which is
formed by treating silica having reactive OH groups with a
dialkylmagnesium in a solvent. Then adding to said solvent a
carbonyl containing compound to form an intermediate which is
subsequently treated with a transition metal to form a catalyst
precursor. The catalyst precursor is activated with
triethylaluminum. This invention relates to the in-situ generation
of internal donor due to the addition of carbonyl compound.
[0005] CN 104974283 describes the catalyst component obtained by
loading magnesium/titanium-containing solid with at least one
inorganic titanium compound, at least one organic titanium
compound, at least one electron donor compound and at least one
activator. The magnesium titanium-containing solid is prepared by
the following method: dissolving magnesium compound in a solvent
system comprising organic epoxy compound and organophosphorus
compound to form a homogeneous solution, and co-precititating with
titanium compound and one or more organic ester compound in the
presence of composite co-precipitant. The catalyst component has
relatively narrow particle size distribution and small ay. particle
size. The catalyst has high activity and high hydrogen response,
and can get polymer with low fines content. This invention also
describes the usage of organic ester as internal donor to improve
catalyst property.
[0006] U.S. Pat. No. 6,803,338 describes the solid titanium
catalyst used for homo- and co-polymerization of ethylene, having
excellent in catalytic activity and producing polymers with a high
bulk density and less polymer soluble in the medium. The solid
titanium catalyst is produced by Step (i) producing a magnesium
solution by contact-reacting a halogenated magnesium compound and
alcohol, Step (ii) reacting the solution with a phosphorus compound
and an ester compound having at least one hydroxy group, and Step
(iii) adding thereto a mixture of a titanium compound and a silicon
compound.
[0007] Hence, there is always a need of better catalyst as well as
polymerization processes which give better performance in cost
effective manner.
SUMMARY OF THE INVENTION
[0008] Accordingly, the present invention provides a process for
preparing catalyst for polymerization of ethylene using magnesium
based precursor along with transition metal. The said catalyst is
prepared using single contact with transition metal compound and no
internal donor is added during the preparation. The amount of
transition metal compound used in the present invention is lower
than the amount which is generally used for the polyethylene
catalyst synthesis. The said catalyst is highly active for ethylene
polymerization and exhibits excellent hydrogen response with
improved hexane soluble due to negligible production of side/by
products.
[0009] Accordingly, the present invention provides a process for
preparing catalyst for the polymerization of ethylene consisting
essentially of the steps of:
[0010] contacting a magnesium based precursor with a solvent; and
(ii) then contacting the magnesium based precursor in the solvent
with a transition metal compound to obtain the catalyst, wherein
step (ii) is single contact step.
[0011] In an embodiment of the present invention, the solvent is
aromatic or aliphatic and polar or non polar in nature, and is
selected from group comprising of benzene, decane, kerosene, ethyl
benzene, chlorobenzene, dichlorobenzene, toluene, o-chlorotoluene,
xylene, dichloromethane, chloroform, cyclohexane and combination
thereof.
[0012] In one of the embodiment of the present invention the
contact time with the solvent in step (i) is immediate to 5 h.
[0013] In yet another embodiment of the present invention, the
contact temperature with the solvent in step (i) is from 10.degree.
C. to 200.degree. C.
[0014] In another embodiment of the present invention, the
magnesium based precursor contains magnesium which is liquid or
solid in nature.
[0015] In yet another embodiment of the present invention, the
magnesium based precursor is liquid in nature and prepared by
contacting magnesium source with organohalide and alcohol in
presence of the solvent in a single step.
[0016] In another embodiment of the present invention, the
magnesium based precursor is solid in nature and is prepared by
first contacting the magnesium source with organohalide in presence
of solvating agent as the first step and then followed by addition
of alcohol.
[0017] In one embodiment of the present invention, the magnesium
based precursor is contacted with solvent prior to transition metal
contact.
[0018] In yet another embodiment of the present invention, the
transition metal compound is represented by M(OR).sub.pX.sub.4-p,
where M is selected from a group comprising of Ti, V, Zr, and Hf,;
X is a halogen atom; R is a hydrocarbon group and p is an integer
having value equal or less than 4, the transition metal compound is
selected from a group comprising of transition metal tetrahalide,
alkoxy transition metal trihalide/aryloxy transition metal
trihalide, dialkoxy transition metal dihalide, trialkoxy transition
metal monohalide, tetraalkoxy transition metal, and mixtures
thereof; wherein: [0019] (a) the transition metal tetrahalide is
selected from a group comprising of titanium tetrachloride,
titanium tetrabromide and titanium tetraiodide and the likes for V,
Zr and Hf; [0020] (b) alkoxy transition metal trihalide/aryloxy
transition metal trihalide is selected from a group comprising of
methoxytitanium trichloride, ethoxytitanium trichloride,
butoxytitanium trichloride and phenoxytitanium trichloride and the
likes for V, Zr and Hf; [0021] (c) dialkoxy transition metal
dihalide is diethoxy titanium dichloride and the likes for V, Zr
and Hf; [0022] (d) trialkoxy transition metal monohalide is
triethoxy titanium chloride and the likes for V, Zr and Hf; and
[0023] (e) tetraalkoxy transition metal is selected from a group
comprising of tetrabutoxy titanium and tetraethoxy titanium and the
likes for V, Zr and Hf.
[0024] In yet another embodiment of the present invention, the
contact temperature with the transition metal compound in step (ii)
is between -50.degree. C. and 150.degree. C.
[0025] In yet another embodiment of the present invention, the
titanium compound is added in amounts ranging from 1 to 20 moles
with respect to one mole of magnesium.
[0026] In yet another embodiment of the present invention, the
transition metal compound is used either neat or in solvent and
wherein the solvent is selected from a group comprising of
chlorinated aromatic hydrocarbon, non chlorinated aromatic
hydrocarbon, chlorinated aliphatic hydrocarbon, non chlorinated
aliphatic hydrocarbon and combination thereof.
[0027] In yet another embodiment of the present invention, the
solvent comprises from 40 to 60 volume percent and selected from a
group comprising of benzene, decane, kerosene, ethyl benzene,
chlorobenzene, dichlorobenzene, toluene, o-chlorotoluene, xylene,
dichloromethane, chloroform, cyclohexane and combination
thereof.
[0028] In yet another embodiment of the present invention, the
contact temperature with the transition metal compound in step (ii)
is between -50.degree. C. and 150.degree. C. and heating is
instigated at a rate of 0.1 to 10.0.degree. C./minute.
[0029] The present invention also provides a catalyst comprising
1.0 wt % to 14 wt % of titanium and 10 wt % to 20 wt % of
magnesium.
[0030] The present invention also provides a process for
preparation of a catalyst system, said process comprising
contacting the catalyst with at least one cocatalyst, and
optionally with an external electron donor to obtain the catalyst
system.
[0031] The present invention also provides a process of
polymerizing and/or copolymerizing of ethylene to obtain a
polyethylene said process comprising the step of contacting an
ethylene under a polymerizing condition with the catalyst
system.
BRIEF DESCRIPTION OF DRAWING
[0032] FIG. 1: XRD of the catalyst of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The present invention discloses the process of preparation
of catalyst for the polymerization of ethylene where the magnesium
based precursor is contacted with transition metal. The said
catalyst is able to polymerize olefins with high activity and
excellent hydrogen response.
[0034] The present invention describes the process of preparation
of catalyst. In an embodiment, the solid catalyst is prepared
through the process which requires contacting magnesium based
precursor with transition metal. In another embodiment, the
magnesium based precursor used in the present invention is prepared
through the process as described in WO2014/045260 and
WO2014/045259.
[0035] According to the present invention, the magnesium based
precursor contains magnesium and may be liquid or solid in nature.
In an embodiment, the magnesium based precursor is liquid in nature
and prepared by contacting magnesium source with organohalide and
alcohol in presence of the solvent in a single step.
[0036] In an embodiment, the magnesium based precursor is solid in
nature and is prepared by first contacting the magnesium source
with organohalide in presence of solvating agent as the first step
and then followed by addition of alcohol. The solid magnesium based
precursor is obtained either by removal of solvating agent or by
precipitation methodology.
[0037] The present invention describes the process of preparation
of catalyst. The solid catalyst is prepared through the process
which requires contacting magnesium based precursor with transition
metal in presence of solvent. In an embodiment, the magnesium based
precursor is contacted with solvent prior to transition metal
contact. In another embodiment, the solvent can be aromatic or
aliphatic and polar or non polar in nature, examples not limiting
to benzene, decane, kerosene, ethyl benzene, chlorobenzene,
dichlorobenzene, toluene, o-chlorotoluene, xylene, dichloromethane,
chloroform, cyclohexane etc. In another embodiment, the contact
time with the solvent is immediate to 5 h. In one of the preferred
embodiment the contact time with the solvent is immediate to 1 h.
In one of the more preferred embodiment the contact time with the
solvent is immediate to 0.5 h. In another embodiment, the contact
temperature is from 10.degree. C. to 200.degree. C. In one of the
preferred embodiment, the contact temperature is from 20.degree. C.
to 120.degree. C.
[0038] The magnesium based precursor is contacted with the solvent
where either the precursor can be added to the solvent or solvent
can be added to the precursor.
[0039] The present invention describes the process of preparation
of catalyst. In an embodiment, the magnesium based precursor in the
solvent is treated with transition metal selected from compounds
represented by M(OR).sub.pX.sub.4-p, where M is a transition metal
and is selected from a group comprising of Ti, V, Zr, and Hf,
preferably Ti; X is a halogen atom; R is a hydrocarbon group and p
is an integer having value equal or less than 4. In yet another
embodiment of the present invention, the transition metal compound
represented by M(OR).sub.pX.sub.4-p is selected from a group
comprising of transition metal tetrahalide, alkoxy transition metal
trihalide/aryloxy transition metal trihalide, dialkoxy transition
metal dihalide, trialkoxy transition metal monohalide, tetraalkoxy
transition metal, and mixtures thereof; wherein: [0040] (a) the
transition metal tetrahalide is selected from a group comprising of
titanium tetrachloride, titanium tetrabromide and titanium
tetraiodide and the likes for V, Zr and Hf; [0041] (b) alkoxy
transition metal trihalide/aryloxy transition metal trihalide is
selected from a group comprising of methoxytitanium trichloride,
ethoxytitanium trichloride, butoxytitanium trichloride and
phenoxytitanium trichloride and the likes for V, Zr and Hf; [0042]
(c) dialkoxy transition metal dihalide is diethoxy titanium
dichloride and the likes for V, Zr and Hf; [0043] (d) trialkoxy
transition metal monohalide is triethoxy titanium chloride and the
likes for V, Zr and Hf; and [0044] (e) tetraalkoxy transition metal
is selected from a group comprising of tetrabutoxy titanium and
tetraethoxy titanium and the likes for V, Zr and Hf.
[0045] The contact temperature with the transition metal compound
is between about -50.degree. C. and about 150.degree. C. In one of
the preferred embodiment, the contact temperature with the
transition metal compound is between about -30.degree. C. and about
120.degree. C.
[0046] A person skilled in the present art knows that the titanium
to magnesium mole ratios used for catalyst synthesis are about 20
to 80 moles. In an embodiment, the titanium compound is added in
amounts ranging from about at least 1 to 20 moles, with respect to
one mole of magnesium. In one of the preferred embodiment, the
titanium compound is added in amounts ranging from about at least 5
to 15 moles, with respect to one mole of magnesium. However usage
of higher titanium compound is neither advantageous nor detrimental
to catalyst synthesis process.
[0047] A person skilled in the present art knows that the contact
of the magnesium based precursor with transition metal compound is
generally twice or more. In an embodiment, the contact of the
magnesium based precursor with transition metal compound in
presence of the solvent is single. However multiple contact with
transition metal compound is neither advantageous nor detrimental
to catalyst synthesis process.
[0048] In an embodiment, the transition metal compound can be used
either neat or in solvent which can be chlorinated or non
chlorinated aromatic or aliphatic in nature, examples not limiting
to benzene, decane, kerosene, ethyl benzene, chlorobenzene,
dichlorobenzene, toluene, o-chlorotoluene, xylene, dichloromethane,
chloroform, cyclohexane and the like, comprising from 40 to 60
volume percent. In another embodiment, this treatment is either one
shot or dropwise or controlled.
[0049] In a preferred embodiment, this reaction system is gradually
heated to the temperature effective to carry out the reaction,
preferably from about -50.degree. C. and about 150.degree. C. In
one of the more preferred embodiment, reaction system is gradually
heated to the temperature effective to carry out the reaction from
about -30.degree. C. and about 120.degree. C. The heating is
instigated at a rate of 0.1 to 10.0.degree. C./minute, or at a rate
of 1 to 5.0.degree. C./minute. The resultant is the solid component
in the solvent comprising of magnesium, transition metal and
halogen components.
[0050] The resulting solid component comprising of magnesium,
transition metal and halogen can be separated from the reaction
mixture either by filtration or decantation and washed with solvent
to remove unreacted component and other side products. In an
embodiment, the resultant solid component is washed one or more
time with chlorinated or non chlorinated aromatic or aliphatic
solvent, examples not limiting to benzene, decane, kerosene, ethyl
benzene, chlorobenzene, dichlorobenzene, toluene, o-chlorotoluene,
xylene at temperature from about 80.degree. C. to about 120.degree.
C.
[0051] The solid catalyst is separated from the above solvent
either by filtration or decantation and finally washed with inert
solvent to remove unreacted component and other side products.
Usually, the resultant solid material is washed one or more times
with inert solvent which is typically a hydrocarbon including, not
limiting to aliphatic hydrocarbon like isopentane, isooctane,
hexane, pentane or isohexane. In an embodiment, the resulting solid
mixture is washed one or more times with inert hydrocarbon based
solvent preferably, hexane at temperature from about 20.degree. C.
to about 80.degree. C. In one of the more preferred embodiment, the
resulting solid mixture is washed at temperature from about
25.degree. C. to about 70.degree. C. The solid catalyst can be
separated and dried or slurried in a hydrocarbon specifically heavy
hydrocarbon such as mineral oil for further storage or use.
[0052] In an embodiment, the catalyst includes from about 1.0 wt %
to 14 wt % of titanium and magnesium is from about 10 wt % to 20 wt
%.
[0053] The catalyst synthesis process as described in the present
invention is a simple process where harsh chemicals based on
transition metals are used in relatively lesser amount. It is also
the advantage of this process that it doesn't require higher
temperatures and longer time periods for catalyst synthesis.
[0054] XRD measurement of representative catalyst which is
synthesized from the process described in present invention
provided following features: 1) 9-18.degree.: broad peak, 2)
27-38.degree.: broad peak, 3) 43.degree. broad halo, 4)
48-54.degree.: broad peak, and 5) 57-67.degree.: broad halo. The
broad peaks & halo emerge due to the distortion in the MgC12
structure attributed to the changes in the regular arrangement of
Cl--Mg--Cl triple layers in MgCl.sub.2 providing desired
active/disordered MgC12 required for high activity catalysts.
Deconvolution of XRD enabled the calculation of crystallite size
which falls in the range of 5-15 nm. FIG. 1 shows the XRD data of
the said catalyst of the present invention.
[0055] The present invention provides the catalyst system for
polymerization and/or copolymerization of ethylene. In the
embodiment, the method of polymerization process is provided where
the catalyst system is contacted with ethylene typically in the
presence of hydrogen, under polymerization conditions. The catalyst
system includes the said catalyst, organoaluminum compounds and/or
external electron donors. The co-catalyst may include hydrides,
organoaluminum, lithium, zinc, tin, cadmium, beryllium, magnesium,
and combinations thereof. In an embodiment, the preferred
co-catalyst is organoaluminum compounds.
[0056] In an embodiment, the organoaluminum compounds include, not
limiting to, alkylaluminums such as trialkylaluminum such as
preferably triethylaluminum, triisopropylaluminum,
triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum,
tri-n-octylaluminum; trialkenylaluminums such as triisoprenyl
aluminum; dialkylaluminum halides such as diethylaluminum chloride,
dibutylaluminum chloride, diisobutylaluminum chloride and diethyl
aluminum bromide; alkylaluminum sesquihalides such as ethylaluminum
sesquichloride, butylaluminum sesquichloride and ethyl aluminum
sesquibromide; dialkyl aluminum hydrides such as diethylaluminum
hydride and dibutylaluminum hydride; partially hydrogenated
alkylaluminum such as ethylaluminum dihydride and propylaluminum
dihydride and aluminoxane such as methylaluminoxane,
isobutylaluminoxane, tetraethylaluminoxane and
tetraisobutylaluminoxane; di ethyl aluminum ethoxide.
[0057] The mole ratio of aluminum to titanium is from about 5:1 to
about 500:1. In one of the preferred embodiment, the mole ratio of
aluminum to titanium is from about 10:1 to about 250:1. In one of
the most preferred embodiment, the mole ratio of aluminum to
titanium is from about 25:1 to about 100:1.
[0058] In one embodiment, the ethylene is polymerized under mild
conditions in an inert hydrocarbon medium. In another embodiment,
inert hydrocarbon medium include aliphatic hydrocarbons such as
propane, butane, isobutane, pentane, hexane, heptane, octane,
decane, dodecane and kerosene; alicyclic hydrocarbons such as
cyclopentane, cyclohexane and methylcyclopentane; aromatic
hydrocarbons such as benzene, toluene and xylene, liquid olefins
and mixtures thereof.
[0059] The catalyst system is contacted with olefin under
polymerization conditions to produce desired polymer products. The
polymerization process can be carried out such as by slurry
polymerization using an inert hydrocarbon solvent as a diluent, or
bulk polymerization using the liquid monomer as a reaction medium
and in gas-phase operating in one or more fluidized or mechanically
agitated bed reactors. In an embodiment, polymerization is carried
out as such. In another embodiment, the copolymerization is carried
out using at least two polymerization zones. In particular, said
catalyst can be used to produce, the following products such as
high-density polyethylene (HDPE, having a density higher than 0.940
g/cm.sup.3), which includes ethylene homopolymer and copolymer of
ethylene and .alpha.-olefins having 3 to 12 carbon atoms; linear
low-density polyethylene (LLDPE, having a density lower than 0.940
g/cm.sup.3), and very low density and ultra low density
polyethylene (VLDPE and ULDPE, having a density lower than 0.920
g/cm.sup.3, and as low as 0.880 g/cm.sup.3), consisting of the
copolymer of ethylene and one or more .alpha.-olefins having 3 to
12 carbon atoms, wherein the molar content of the unit derived from
ethylene is higher than 80%; elastomeric copolymer of ethylene and
propylene, and elastomeric terpolymers of ethylene, propylene and
butene-1 as well as diolefins at a small ratio, wherein the weight
content of the unit derived from ethylene is between about 30% and
70%.
[0060] The polymerization is carried out at a temperature from 0 to
250.degree. C., preferably from 20 to 200.degree. C. When the
polymerization is carried out in gas phase, operation pressure is
usually in the range of from 5 to 100 bar preferably from 10 to 50
bar. The operation pressure in slurry polymerization is usually in
the range of from 1 to 10 bar, preferably from 2 to 7 bar. The
operation pressure in solution polymerization is usually in the
range of from 1 to 10 bar, preferably from 2 to 7 bar. Hydrogen can
be used to control the molecular weight of polymers.
[0061] The catalyst described in the present invention provides
polyethylene with narrow particle size distribution, excellent bulk
density and broad molecular weight distribution.
[0062] In the present invention, the described catalyst can be
directly added to the reactor for polymerization or can be
prepolymerized i.e. catalyst is subjected to a polymerization at
lower conversion extent before being added to polymerization
reactor. Prepolymerization can be performed with ethylene where the
conversion is controlled in the range from 0.2 to 500 gram polymer
per gram catalyst.
[0063] In the present invention, the inventors surprisingly found
that the described catalyst shows excellent hydrogen response even
in the absence of internal donor and/or external donor with broad
molecular weight distributions.
[0064] In an embodiment, the polyethylenes produced by the said
described catalyst have melt flow indexes (Ml, measured according
to ASTM standard D 1238)) from about 0.001 to about 3,000 dg/min,
preferably from about 0.005 to about 1,000 dg/min, more preferably,
from about 0.02 to about 10 dg/min.
[0065] The melt flow ratio (MFR) or 121.6/12.16 is determined by
ASTM standard D1238 where 121.6 is a melt index of the polymer
measure at 190.degree. C. under a load of 21.6 kg and 12.16.is a
melt index of the polymer measure at 190.degree. C. under a load of
2.16 kg. Higher MFR indicates a broad molecular weight
distribution. In another embodiment, the polyethylenes produced by
the said described catalyst show higher MFR.
[0066] The present invention provides the catalyst system. The
catalysts system when polymerizes ethylene provides polyethylene
having bulk densities (BD) of at least about 0.35 cc/g.
[0067] Having described the basic aspects of the present invention,
the following non-limiting examples illustrate specific embodiment
thereof.
A-Magnesium Based Precursor Synthesis
Example 1: Liquid Magnesium Based Precursor
[0068] In 500 ml glass reactor maintained at 25 .degree. C.,
calculated amount of magnesium (powder or turnings) were weighed
and added into the reactor followed by addition of calculated
amount of organohalide followed by alcohol in toluene. This mixture
was stirred and gradually heated to 90.degree. C..+-.3. After the
activation of the reaction, the mixture was allowed to be
maintained at same temperature for 6 h. The resulting solution was
viscous in nature. The organomagnesium compounds synthesized by the
above procedure have been tabulated in Table 1.
TABLE-US-00001 TABLE 1 Liquid Precursor Benzyl Mg chloride Alcohol
Mg Precursor Ratio Ratio Ratio Solvent Alcohol (wt %) MGP#PM- 1 1.1
1.2 toluene 2-ethyl- 1.1 018 1-hexanol
Example 2: Solid Magnesium Based Precursor
[0069] In 500 ml glass reactor maintained at 0.degree. C.,
calculated amount of magnesium (powder or turnings) were weighed
and added into the reactor followed by addition of calculated
amount of organohalide followed by diethyl ether. This mixture was
stirred and after the activation of the reaction, the mixture was
allowed to be maintained at same temperature until all magnesium
has reacted. To the resulting solution, the calculated amount of
alcohol was added dropwise over a period of 1-2 h. After the
completion of addition, the solution was allowed to stir for
another 0.5 h. Finally, ether was evaporated and solid compound was
analyzed. In case of precipitation methodology, the resulting
solution prepared using magnesium and organohalide in diethyl ether
was precipitated out in the desired amount of alcohol/hexane
mixture.
TABLE-US-00002 TABLE 2 Solid magnesium based precursor Benzyl Mg
chloride Alcohol Mg Cl Precursor Ratio Ratio Ratio Solvent Alcohol
(wt %) (wt %) MGP#106 1 1 1.1 diethylether ethanol 17.1 30.1
MGP#169 1 1 1.2 diethylether Isobutanol 14.2 23.6 MGP#172 1 1 1.2
diethylether 2-ethyl- 12.0 18.1 1-hexanol MGP#175 1 1 1.2
diethylether ethanol 17.5 30.3 MGP#176 1 1 1.2 diethylether ethanol
17.6 30.5 MGP#PM-007 1 1 1.2 diethylether ethanol 16.9 29.4
B-Catalyst Synthesis
[0070] Into a three neck 500 ml jacketed reactor, added weighed
amount of magnesium based precursor and 100 ml of dry chlorobenzene
and stirred for 10-15 min at 40.degree. C. To this added 60 ml of
neat TiCl.sub.4 and temperature was increased from 40.degree. C. to
110.degree. C. This mixture was heated to 110.degree. C. for 2 h.
The mixture was allowed to settle followed by decantation. The
solid component was washed with chlorobenzene at 110.degree. C. and
allowed to settle again, followed by decantation. The solid
component was washed with hexane four times at 65.degree. C. and
dried under nitrogen till free flowing powder was obtained.
TABLE-US-00003 TABLE 3 Catalyst synthesis Solvent for Mg Ti Cat No
MGP# Dispersion Titanation wt % wt % D50 PEC#31 MGP#106
chlorobenzene 2 h @ 110.degree. C. 16.8 7.5 10.5 PEC#113 MGP#175
chlorobenzene 1 h @ 110.degree. C. 15.2 5.9 10.3 (4.6 g) PEC#114
MGP#175 chlorobenzene 4 h @ 110.degree. C. 19.0 7.0 11.0 (4.4 g)
PEC#115 MGP#175 chlorobenzene 2 h @ 110.degree. C. 15.7 5.8 10.7
(4.5 g) PEC#116 MGP#175 chlorobenzene 2 h @ 110.degree. C. 14.5 6.6
11.5 (4.5 g) 30 ml TiCl.sub.4 PEC#117 MGP#176 chlorobenzene 2 h @
110.degree. C. 19.5 6.2 16.3 (4.6 g) PEC#118 MGP#175 chlorobenzene;
2 h @ 110.degree. C. 16.7 1.4 11.1 (4.5 g) Benzoyl chloride
addition PEC#119 MGP#175 chlorobenzene 2 h @ 110.degree. C. 17.4
6.4 10.0 (5.7 g) PEC#122 MGP#169 chlorobenzene 2 h @ 110.degree. C.
15.6 8.8 35.6 (4.5 g) PEC#109 MGP#172 chlorobenzene 2 h @
110.degree. C. 13.0 7.8 26.2 (15.6 g) PEC#123 MGP#169 chlorobenzene
2 titanations 17.1 4.7 59.6 (4.5 g) 1 h @ 110.degree. C. PEC#124
MGP#175 chlorobenzene 2 titanations 16.0 5.1 10.6 (4.5 g) 1 h @
110.degree. C. PEC#125 MGP#172 chlorobenzene 2 titanations 16.6 3.9
63.5 (4.6 g) 1 h @ 110.degree. C. PEC#126 MGP#176 chlorobenzene 2 h
@ 110.degree. C. 17.2 5.6 20.7 (4.5 g) PEC#127 MGP#175
chlorobenzene 2 h @ 110.degree. C. 16.6 6.3 10.0 (4.6 g) PEC#128
MGP#175 chlorobenzene 2 h @ 110.degree. C. 16.0 5.2 9.6 (4.6 g)
PEC#129 MGP#175 chlorobenzene 2 h @ 110.degree. C. 16.6 5.5 10.0
(4.5 g) PEC#135 MGP#178 chlorobenzene 2 h @ 110.degree. C. 15.0 2.3
11.6 (4.5 g) Tetraethoxysilane/ Ethylbenzoate as Internal donor
PEC#174 MGP#PM-007 chlorobenzene 2 h @ 110.degree. C. 17.2 5.8 11.2
(6.6 g)
[0071] Table 4 describes the catalyst synthesized using the same
precursor and under simular conditions
TABLE-US-00004 TABLE 4 Solvent for Mg Ti D50 Cat No MGP# Dispersion
Titanation wt % wt % microns PEC#156 MGP#PM-007 chlorobenzene 2 h @
110.degree. C. 18.2 5.3 10.2 (6.6 g) PEC#160 MGP#PM-007
chlorobenzene 2 h @ 110.degree. C. 20.1 2.5 20.4 (6.6 g) Ethyl
benzoate as internal donor On addition of internal donor, the
catalyst mean particle size (D50) increases.
[0072] Table 5 shows the above catalysts evaluation for ethylene
polymerization
TABLE-US-00005 TABLE 5 POLYMER ANALYSIS CATALYST POLYMERIZATION MFI
Hexane Bulk Cat wt Al/Ti H2 Activity @5 kg MFR Solubles density Cat
No (mg) ratio Kg/cm.sup.2 kgPE/gcat dg/min I.sub.21.6/I.sub.2.16 wt
% g/cc PEC#156 50.0 80 1 2.9 20.1 36 0.3 0.42 PEC#160 50.4 80 1 1.5
1.7 ND* 0.2 0.41
[0073] The above table clearly shows the higher activity with
better hydrogen response for the catalyst as prepared by the
described process in the invention as compared to the catalyst
having internal donor.
C-Ethylene Polymerization
[0074] Polymerization of ethylene was carried out in 500 ml Buchi
reactor which was previously conditioned under nitrogen. The
reactor was charged with 250 ml of dry hexane containing solution
of 10 wt % triethylaluminum and calculated amount of solid
catalyst. The reactor was pressurized with hydrogen to 14.2 psi
then charged with 71 psi of ethylene under stirring at 750 rpm. The
reactor was heated to and then held at 70.degree. C. for 2 hour. At
the end, the reactor was vented and the polymer was recovered at
ambient conditions.
[0075] Catalyst performance and polymer properties are tabulated in
Table 6.
TABLE-US-00006 TABLE 6 Ethylene polymerization POLYMER ANALYSIS
CATALYST POLYMERIZATION MFI Hexane Bulk Cat wt Al/Ti H2 Activity @5
kg MFR Solubles density Cat No (mg) ratio Kg/cm.sup.2 kgPE/gcat
dg/min I.sub.21.6/I.sub.2.16 wt % g/cc PEC#113 15.1 80 1 5.8 3.0
33.8 0.13 0.39 15.2 80 2 3.3 16.4 35.4 0.92 0.40 PEC#114 15.4 80 1
6.6 7.0 37.9 0.43 0.40 15.3 80 2 4.2 55.7 ND* 1.3 0.40 PEC#115 15.4
80 1 6.4 6.0 34.5 0.93 0.40 15.6 80 2 4.2 47.5 3.6 0.70 0.40
PEC#116 15.6 80 1 4.8 2.5 35.5 0.30 0.39 15.4 80 2 4.4 50.4 3.5
1.30 0.40 PEC#117 15.7 80 1 4.2 1.9 36.9 0.27 0.39 15.4 80 2 1.4
ND* 11.4 0.54 0.37 PEC#119 15.2 80 1 5.7 3.4 34.8 0.69 0.40 PEC#122
15.0 80 1 1.5 0.4 56.7 0.91 0.32 PEC#109 15.1 80 1 1.8 ND* 45.2
0.61 0.38 PEC#123 15.2 80 1 0.4 ND* ND* 0.6 ND* PEC#124 15.1 80 1
5.2 4.2 36.4 0.30 0.40 PEC#125 15.4 80 1 0.5 ND* ND* 0.40 ND*
PEC#126 15.3 80 1 4.6 3.5 37.3 0.24 0.40 PEC#127 15.2 80 1 6.3 7.2
24.9 0.40 0.40 15.3 80 2 3.5 22.4 39.4 0.90 0.40 PEC#135 25 80 1
1.6 ND* ND* 0.06 0.40 PEC#178 50.2 80 1 3.2 18.7 ND* 0.3 0.38
[*ND--Not Determine]
D-Hydrogen Response
[0076] Table 7 shows the hydrogen response of the said catalyst of
the present invention
TABLE-US-00007 TABLE 7 POLYMER ANALYSIS CATALYST POLYMERIZATION MFI
Hexane Bulk Cat wt Al/Ti H2 Activity @5 kg MFR Solubles density Cat
No (mg) ratio Kg/cm.sup.2 kgPE/gcat dg/min I.sub.21.6/I.sub.2.16 wt
% g/cc PEC#174 50.4 80 0.5 2.3 2.8 ND* 0.3 0.39 50.3 80 1 2.2 19.4
ND* 0.4 0.38 50.4 80 1.5 1.7 64.8 ND* 1.2 0.37 50.0 80 2 1.3 119.5
ND* 1.6 0.37
[0077] The said catalyst of the present invention shows good
hydrogen response as indicated above in the table. As the
concentration of the hydrogen is increased, the activity of the
catalyst lowers while the melt flow increases indicating that lower
molecular weight polyethylene is being formed at higher hydrogen
concentrations but the hexane solubles does not increase beyond 2
wt %.
E-Copolymerization
[0078] The said catalyst of the present invention was evaluated for
copolymerization of ethylene with 1-butene. Table 8 describes the
polymerization conditions and the polymer analysis data. The trend
of the addition of the monomer was 1-butene followed by hydrogen
and then ethylene. 1-butene was charged through MFC and catalyst
was charged at 10.degree. C.
TABLE-US-00008 TABLE 8 POLYMER ANALYSIS CATALYST POLYMERIZATION MFI
Hexane Bulk Cat wt Al/Ti H2 Activity 1-butene @2.16 kg Solubles
density T.sub.C Cat No (mg) ratio Kg/cm.sup.2 kgPolymer/gcat L
dg/min wt % g/cc .degree. C. PEC#31 15.1 80 2 6.4 4.4 15.5 4.6 ND
126.7 15.5 80 2 4.6 2 18.9 2.2 0.35 129.7 15.2 80 2 5.1 3 28.7 1.3
0.3 128.8 15.1 80 2 4.6 1 23.9 1.6 0.31 128.7 *PE#237
[0079] The incorporation of 1-butene and the percentage
incorporation in the copolymer was determined through .sup.13C NMR.
Table 9 describes the data.
TABLE-US-00009 TABLE 9 S. No. Br/1000 C. Butene-1 mol % Type of
Branch PE#237 12.9 2.7 Ethyl
* * * * *